watchOS 5.1.2 (build 16S46) is an official Apple over-the-air update for the Apple Watch Series 1 (38mm), released on 2018-12-06T18:04:02Z. The update package is 971.1 MB. This is a delta (partial) update that requires 3.0 already installed. This update is no longer signed by Apple, meaning it can no longer be applied on-device through Settings.

Payload file: 8c19168d719e32a808194738d5159db0c9c78431.zip.